Portrayed by Julia Jones
Leah Clearwater is the only known female shape-shifting wolf in the history of the Quileute tribe. She is the smallest wolf, has light gray fur, and is the fastest in the pack. At the age of 19, she transforms into a wolf during the events of New Moon, around the same time as her younger brother, Seth. This transformation is believed to be what caused the heart attack and subsequent death of their father, Harry. She dated Sam Uley for years until her second cousin Emily came to visit and Sam imprinted on her. Sam thus left her for Emily, leaving Leah broken-hearted. She puts up a brave face, though, and in Eclipse it is suggested that she intends to serve as bridesmaid at Sam and Emily's wedding. Despite this, she is disliked by her pack brothers for her very bitter and cynical attitude. She constantly antagonizes the pack by thinking about things that make the others uncomfortable, such as Embry's paternity.
In Breaking Dawn, Leah joins Jacob's pack with the intention of breaking free of Sam, since she is still heartbroken. She helps to protect Bella and the Cullens, despite her extreme hatred for vampires and her open dislike for Bella. She shares her insecurities with Jacob, such as the reasons for Sam's imprinting on Emily, her regrets that she might be menopausal due to her transformation, and her inability to rise higher in pack rank due to her gender. As she spends more time in Jacob's pack, she becomes happier, makes notable changes in her attitude, and is less negative. Later in the book, Jacob and Leah's feelings toward each other become a trusted comradeship, though they conceal their fondness for each other by constantly bickering. She displays quite a bit of loyalty to him, and even angrily confronts Bella about her unfair treatment of Jacob and the pain she has caused him. By the end of the novel, Leah has replaced Seth as Jacob's second-in-command.